The proposed research is aimed at bridging the gap of knowledge between the biochemistry, ultrastructure and cell physiology of cell structure and motility especially in amoeboid cells. The investigations center around functional cell extracts from amoeboid cells which can be regulated to exhibit gelation-solation and contraction. Specific proteins will be isolated from the extracts and the interaction of these proteins with actin and myosin will be investigated by standard solution biochemical techniques and fluorescence spectroscopy. Finally, the distribution and interaction of these fluorescently labeled cytoskeletal and contractile proteins will be studied in living cells using our technique of Molecular Cytochemistry. Quantitative spectroscopic techniques will also be tested on living cells using a microspectrofluorometer.